What are my genes (and proteins) doing now?

22 Oct

Courtesy of the U.S. Department of Energy Genome Programs, http://genomics.energy.gov

Genes need to live in almost all of my cells because without them, those cells could neither function nor replicate.

Making new cells, making proteins

Through mitosis, my older cells are, right now as I write this sentence, duplicating their genetic information so that they can split into two “daughter” cells, keeping my body fresh. The dead skin cells I rubbed off in the shower this morning revealed younger, genetically identical cells that, because of mitosis, were there to replace what my loofah scraped away.

Another function of the genes in my cells is to provide the “recipes” (in the form of DNA sequences of As, Gs, Ts and Cs) that are used to make proteins.

(Link here to the University of Utah’s Genetic Science Learning Center to use an interactive learning tool and see how DNA is transcribed and translated.)

What is a protein?

Proteins are molecules.  They do everything from make molecular “cash” to haul molecular “manure.”  The can be super-small or gargantuan.  They are made of amino acids (20 types of them) strung together that each have a chemical personality.

They help me digest, move, grow, see, and heal. Some proteins are enzymes, hormones, or antibodies. Some build and replace tissues in your body. Proteins are major components of muscles, organs, skin, hair, fingernails, and blood vessels. They also do all of the heavy lifting inside of your busy cells.  Some proteins are machines that do stuff.  Some proteins are like bricks and mortar that build my body.

Proteins manufacture a cell’s structures, and they will keep the cell stable, keep it responsive and relating to its neighbors. Genes provide instructions for making amino acids, and what the amino acids strung together do is really create little molecular machines.

Some proteins are tunnels in the cell membrane, or channels, that only open and close when the right energy packet comes along to open them– almost like putting a quarter in a tollbooth bucket to get the gate to open.

Other genes code for structural components that help to keep your cells in a certain shape, whether they are flat, cubic, or long and spindly. Proteins make up the microtubules in cells that are like the flexible beams that shape and hold up a tent.

There are also incredible ear hair cells that dance to the vibrations of words hitting our ears; (in 2004, researchers discovered a protein that helps convert the vibrations into “sound” as it is perceived by the brain).

Other proteins act as chaperones as new proteins are “born.”

When my body makes proteins, (watch this process here), “recipes” written on the DNA inside of a cell’s nucleus are copied for mass production, as if by Xerox, in a form called messenger RNA. Protein complexes then recognize that in order for that freshly made copy of the gene to ever get turned into a protein it has to be moved out of the nucleus and into the cytoplasm (the bulk of the cell that is mostly made out of albumin, the clear gooey stuff that makes egg whites).

So the messenger RNA exits the nucleus through a protein channel, and it then has to be chaperoned through the “endoplasmic reticulum.” (I love this term; it always triggers a Sci-fi spaceship computer voice in my head, announcing: “You are now entering the endoplasmic reticulum.”) Well the endoplasmic reticulum is where the messenger RNA– that fresh copy of the sequence of the gene– is actually made into the protein. It’s like a manufacturing station where a cells makes its widgets. And once the new widget is made, just like in any good manufacturing center, there are other chaperones that take it out into the world. Moving stuff around with accuracy within the cell is a full-time job, and there lots of different proteins that do it.

Interacting with the outside world

There are also whole complexes of proteins that are associated with “signal transduction,” which is really a fancy word for “chemical FedEx.” Through proteins, my body will “FedEx” environmental signals that say, “Turn this gene on, and turn this gene off.” For example, it might say: “Incoming! Just ate burger.” The lipids and vitamins in the food that we eat, among other things, stimulate the world of the genes to “express.”

So what do my genes DO? Well they are there as a repository of information that give me the capability to respond to the ever-changing world– and they are really where everything in a sense comes from in the never-ending pendulum of the outside to inside, inside to outside dance. We take it in, we process and respond. The way we process and respond in turn affects the environment, and again the environment comes back in, and it’s almost like the “Looking Glass” between two worlds.

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